Brake shoe reenforce



July 4, 1933. R. B. PoGuE BRAKE SHOE REENFORCE Filed Jan. 4, 1932 ATTORNEY Patented July 4, 1933A UNITED sTATEs lfATENr oFFIca ROBERT B. POGUE, 0F ORANGE, NEW JERSEY, ASSIGNOR TO lTHE AMERICANBRAKE SHOE AND FOUNDRY COMPANY, OF NEW YORK, N. Y., ACOBPORATION 0F DELA- WARE BRAKE SHOE REENFORCE Application led January 4, 1932. Serial No. 584,741.

This invention relates to the manufacture of reenforces which are embedded in the cast iron body of brake shoes during the casting operation Heretofore it has been the practice to embed a. ductile metal reenforce, commonly called a steel back, in the back of the cast iron body of a shoe to hold the parts of the body together in case of fracture so that the shoe may continue in service. The backs compris-e rods, bars or plates, and the plates have been'perforated, slotted or cut out in a variety of skeleton forms. lt has been proposed also to make the backs of expanded metal and other mesh material. It has also been the practice to providereenforces in the wearing part of the body of the shoe, one kind of reenforce being a bundle of expanded metal which is placed in the mold and embedded in the cast iron body of the shoe, to hold the parts of the body together in case of fracture so that the shoe may continue in service, and for other purposes. Sometimes these bundles are arranged in the body of the shoe so that the expanded metal extends to the back of the body.

It was the practice for a long time to place the reenforces in the mold preliminary to the casting operation without treating the reenforces but it was found that the reenforces would sometimes burn during the casting operation which would render them ineflicient and sometimes wholly ineffective, as a reenforce. To avoid this it then became the practice to lightly coat the reenforces with refractory material by dipping the reenforces in oil and allowing them to drain and then dipping them in silica flour or other such refractory material. Sufficient silica lflour would adhere to the oil surface of the reenforce to form a light coating which has been sufhcient under the general conditions of manufacture to protect the reenforce from burning and losing its natural physical characteristics during the casting operation. The'reenforce is supported in the mold and the hot metal to form the body is then poured into the mold. If the reenforce is not protected, it may burn or carbonize under the heat of the hot metal and lose its physical characteristics', or it may partially unite with the cast ir'on and become brittle and liable to break easily when the shoe fractures and at the point of fracture. When the reenforce lis protected by light coating of refractory material it is less likely to burn or carbonize or to become united with the cast iron body, butit will be firmly held by the cast iron body in intimate Contact therewith throughout its length and under this condition it will be liable to break at a fracture in the body before, and sometimes long before, the body is worn out. area of the reenforce which is freed by the fracture from intimate contact with the cast iron of the body is concentrated at the fracture and does not extend any appreciable distance into the body away from the fracture. In my application Serial N o. 584,7 40 filed January 4, 1932, I have disclosed and claimed my invention of a brake shoe having a reenforce embedded therein so that, in event of fracture of the body of the shoe, the vibration and other strains upon the reenforce will be distributed over a considerable area of the reenforce away from the fracture and this will have the effect of delaying the fatigue and crystallization of the metal reenforce under service conditions and enabling the shoe to give the service expected of it and continue in service until it is worn down to its limit of wear before the reenforce breaks.

, The object of the present invention is to prepare the reenforce for embedment in the body of a brake shoe during the casting operation so that it will not unite with the body or have such intimate contact therewith as to prevent the distribution of vibration and other strains for a considerable area of the reenforce from a fracture in the body.

This is due to the fact that the The invention may be a steel back, a bundle of expanded metal, or any other form of reenforce for which the invention is or may be adapted. The reenforce is first coated with oil, or dippedin a bath of oil of high viscosity having low carbon content and low sulphur, such as black lubricating oil known to the trade as summer and winter black.

kThen before the oil on the reenforce is dry the reinforce is ivena coating of refractory material, suc as Silica flour, which is'applied in any convenient andvsuitable manner, as by dipping the-reenforce in the flour, or by dustin the fiouron the reenforce.y Thenv the sllica coated reenforce is baked in an oven such as a core oven. The temperature in the oven when the coated reenforces are placed. therein should be below the flash point of the oil and the baking step should be continued slowly until the light ends in the oil are completely'evaporated and the coating is converted into a semi-enamel. I have found it desirable to start with a temperature of about 350 F. and to continue the baking step for about thirty' minutes, gradually increasing the temperature. The temperature and period may be varied to satisfydiii'erent conditions within the scope of the invention. The semi-enamel coating produced by the baking step affords a uniform, stable. and improved protection for the reenforce Whichinsures that the reenforce will not be burned in the casting operation and will not be embedded in the body of the shoe in intimate contact therewith. If the baking step is omitted the coating will not stick tightly to the reenforce and will sluf or rub off in handlingT and wash off in the casting operation; but baking the coating on the reenforce causes it to adhere tightly thereto so that it will not sluf or rub of in handling and will not be washed off by the molten metal in' the casting operation.

To enable my invention to be better understood I have illustrated it in two embodiments in the accompanying drawing wherein Fig. 1 is a plan view of a steel back reenforce with the protective coating thereon indicated by stippling.

Fig. 2 is a longitudinal sectional view of a brake shoe having the steel back reenforce of Fig. l embedded therein.

Fig. 3 is a longitudinal sectional view of a reenforce consisting of a bundle of expanded metal.

Fig. 4 is a longitudinal sectional view of a brake shoe having the expanded metal reenforce of Fig. 3 embedded therein, and

Fig. 5 is a transverse sectional view of a brake shoe having the steel back reenforce and the expanded metal reenforce yembedded therein.

Referring to the drawing, 6 is the steel back reenforcel which is shown made in a well known way with bevelled edges 7, slots or cut-outs 8, and recesses 9. This reenforce may or may nbt comprise alug strap 10 which is en aged with the steel back. This insert is em edded in the bod 1l of the brake shoe, and at the backvthereo as shown in Fig. 2, and the lug strap l() with projections 12 from the body constitute the attaching lug of the shoe.

The insert may consist of a bundle 13 of layers of expanded metal laidone uponthe other and fastened together in an suitable manner for convenience in hand ing, said bundle being embedded in the body of the shoe 14, as shown in Fig. 4. The layers may be arranged in any suitable manner but Iv prefer that they should be arranged one upon the other alternately lengthwiseand crosswise of the material, as shown 1n Fig. 3.

The steel back reenforce and the expanded metal reenforce may be used separately, as shown in Figs. 2 and 4, or they may both be used in the same shoe 15, as shown in Fig. 5. Any reenforce used is first coated with oil in any suitable manner and then coated with refractory material and the combined oil refractory coating is baked on the reenforce after which it is in condition to be embedded in the body of the shoe when the shoe is cast. The baked coating will not sluf or rub oi' the reenforce in ordinary handling nor will it wash ofi' in the casting operation but it will adhere tightly to the reenforce and protect the steel back or the expanded metal from burning out or uniting with the body of the shoe during the castingoperationand alsoinsure that the reenforce or reenforces will not have such intimate contact with the body as wi'll prevent the distribution of vibration and other strains for a considerable area of the reenforce from a fracture in the body.

I have described the invention inits preferred form but I reserve the right to make lany changes therein within the scope of the following claims.

I claim:

1. A reenforce for brake shoes having a baked semi-enamel protective coating thereon.

2. A reenforce for brake shoes having a baked semi-enamel protective coating comprising refractory material thereon. A

3. A reenforce for brake shoes having a baked semi-enamel protective coating comprising oil and refractory material thereon.

4. A reenforce for brake shoes having a baked semi-enamel protective coating coinprising lubricating oil and refractory material thereon.

5. A reenforce for brake shoes having a baked semi-enamel protective coating comprising black lubricating oil and powdered refractory material thereon.

6. The herein described method of preparin a reenforce for embedment in a brake shoe uring the casting operation which consists in coating the reenforce with oil, then coating the oiled reenforce with refractory material, and then baking the coated reenforce.

7. The herein described method of preparin a reenforce for embedment in a brake shoe uring the casting operation which consists in coating the reenforce with oil, then coating the oiled reenforce with powdered refractory material, and then baking the coated reenforce.

8. The herein described method of preparing a reenforce for embedment in a brake shoe during the casting operation which consists in coating the reenforce with black lubricating oil of high viscosity, thencoating the oiled reenforce with powdered refractory material, and then bakingthe coated reenforce.

.v ROBERT BPOGUE. 

